A rolling bearing is known as a bearing that supports a rotation shaft of various types of mechanical devices, and the rolling bearing requires reliability so that burning does not occur. Thus, a rolling bearing, in which grease lubrication having high lubrication performance is adopted, has increased even in the case of high-speed rotation application. In the grease lubrication, the inside of the bearing is filled with grease in advance (for example, refer to PTL 1).
FIG. 4 is a sectional view illustrating an example of a rolling bearing of the related art. The rolling bearing is an angular contact ball bearing 90, and a ball 94 is in contact with an inner ring 91 and an outer ring 92 at a predetermined angle (contact angle). In such an angular contact ball bearing 90, a shoulder diameter D2 of the inner ring 91 on the other side in an axial direction (right side in FIG. 4) is longer than a shoulder diameter D1 of the inner ring on one side in the axial direction (left side in FIG. 4) (D1<D2).
As described above, inside the bearing, in other words, in the bearing of which an annular space 93 formed between the inner ring 91 and the outer ring 92 is filled with grease, seals 97 and 98 are provided on both sides of the annular space 93 in the axial direction. In the angular contact ball bearing 90 illustrated in FIG. 4, the seals 97 and 98 are used as labyrinth seals (non-contact seals) in order to realize high-speed rotation. In other words, the seals 97 and 98 form labyrinth clearances 97a and 98a with the inner ring 91, preventing the spill of grease.